Marking Methods may arguably make the best stencils, they can shrink your artwork or create what you want. There will be a one time art upcharge and they will keep your artwork on file for future orders. It's been so long since I've ordered from them I can't recall how much they are but I'm sure they will be the most expensive and probably most cantakerous to order from. They are notorious for being difficult with smaller orders. If you do go with them, insist on the green stencils, not the gold. Their stencils will last hundreds of impressions each. I've gotten easily a hundred impressions from one stencil.
The kind you make from IMG require at least a little learning curve, but it is worth it to make any kind you want on demand in about a half an hour. They will last several dozen impressions before they get still and start to break down. You can make a light box for exposing the stencils for less than thirty bucks and get the stencil supplies for maybe $50. These are great people to work with and they work hard to get knife makers business.